/*
 * Type-safe wrapper for WebGL in GWT.
 * 
 * Copyright (C) 2009 Hao Nguyen
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package gwt.g3d.client.gl2;

import com.google.gwt.core.client.JavaScriptObject;

/**
 * WebGLContextAttributes interface contains drawing surface attributes and is 
 * passed as the second parameter to getContext.
 * 
 * @author hao1300@gmail.com
 */
public class WebGLContextAttributes {
  private final WebGLContextAttributesImpl impl;
  
  public WebGLContextAttributes() {
    impl = JavaScriptObject.createObject().cast();
  }
  
  /**
   * Converts a JavaScriptObject to this WebGLContextAttributes.
   *  
   * @param contextAttribs a JavaScriptObject whose type is 
   *         WebGLContextAttributes.
   */
  WebGLContextAttributes(JavaScriptObject contextAttribs) {
    impl = contextAttribs.cast();
  }
  
  /**
   * Gets the  JavaScriptObject for the 
   * @return
   */
  public JavaScriptObject getGLContextAttributesImpl() {
    return impl;    
  }
  
  /**
   * Default: true. If the value is true, the drawing buffer has an alpha 
   * channel for the purposes of performing OpenGL destination alpha operations 
   * and compositing with the page. If the value is false, no alpha buffer is 
   * available.
   * 
   * @param enable
   */
  public void setAlphaEnable(boolean enable) {
    impl.setAlphaEnable(enable);
  }
  
  /**
   * Default: true. If the value is true, the drawing buffer has a depth buffer 
   * of at least 16 bits. If the value is false, no depth buffer is available.
   * 
   * @param enable
   */
  public void setDepthEnable(boolean enable) {
    impl.setDepthEnable(enable);
  }
  
  /**
   * Default: false. If the value is true, the drawing buffer has a stencil 
   * buffer of at least 8 bits. If the value is false, no stencil buffer is 
   * available.
   * 
   * @param enable
   */
  public void setStencilEnable(boolean enable) {
    impl.setStencilEnable(enable);
  }
  
  /**
   * Default: true. If the value is true and the implementation supports 
   * antialiasing the drawing buffer will perform antialiasing using its 
   * choice of technique (multisample/supersample) and quality. If the value 
   * is false or the implementation does not support antialiasing, no 
   * antialiasing is performed.
   * 
   * @param enable
   */
  public void setAntialiasEnable(boolean enable) {
    impl.setAntialiasEnable(enable);
  }
  
  /**
   * Default: true. If the value is true the page compositor will assume the 
   * drawing buffer contains colors with premultiplied alpha. If the value is 
   * false the page compositor will assume that colors in the drawing buffer 
   * are not premultiplied. This flag is ignored if the alpha flag is false.
   * 
   * @param enable
   */
  public void setPremultipliedAlphaEnable(boolean enable) {
    impl.setPremultipliedAlphaEnable(enable);
  }
  
  /**
   * Default: false. If false, once the drawing buffer is presented as described 
   * in the Drawing Buffer section, the contents of the drawing buffer are 
   * cleared to their default values. All elements of the drawing buffer (color, 
   * depth and stencil) are cleared. If the value is true the buffers will not 
   * be cleared and will preserve their values until cleared or overwritten by 
   * the author.
   * 
   * @param enable
   */
  public void setPreserveDrawingBufferEnable(boolean enable) {
    impl.setPreserveDrawingBufferEnable(enable);
  }

  /**
   * @see #setAlphaEnable(boolean)
   */
  public boolean isAlphaEnable() {
    return impl.isAlphaEnable();
  }
  
  /**
   * @see #setDepthEnable(boolean)
   */
  public boolean isDepthEnable() {
    return impl.isDepthEnable();
  }
  
  /**
   * @see #setStencilEnable(boolean)
   */
  public boolean isStencilEnable() {
    return impl.isStencilEnable();
  }
  
  /**
   * @see #setAntialiasEnable(boolean)
   */
  public boolean isAntialiasEnable() {
    return impl.isAntialiasEnable();
  }
  
  /**
   * @see #setPremultipliedAlphaEnable(boolean)
   */
  public boolean isPremultipliedAlphaEnable() {
    return impl.isPremultipliedAlphaEnable();
  }
  
  /**
   * @see #setPreserveDrawingBufferEnable(boolean)
   */
  public boolean isPreserveDrawingBufferEnable() {
    return impl.isPreserveDrawingBufferEnable();
  }
  
  /**
   * JavaScriptObject that wraps the functionalities of WebGLContextAttributes.
   * 
   * @author hao1300@gmail.com
   */
  private static class WebGLContextAttributesImpl extends JavaScriptObject {
    protected WebGLContextAttributesImpl() {
    }
    
    public native final void setAlphaEnable(boolean enable) /*-{
      this.alpha = enable;
    }-*/;
    
    public native final void setDepthEnable(boolean enable) /*-{
      this.depth = enable;
    }-*/;
    
    public native final void setStencilEnable(boolean enable) /*-{
      this.stencil = enable;
    }-*/;
    
    public native final void setAntialiasEnable(boolean enable) /*-{
      this.antialias = enable;
    }-*/;
    
    public native final void setPremultipliedAlphaEnable(boolean enable) /*-{
      this.premultipliedAlpha = enable;
    }-*/;
    
    public native final void setPreserveDrawingBufferEnable(boolean enable) /*-{
      this.preserveDrawingBuffer = enable;
    }-*/;

    public native final boolean isAlphaEnable() /*-{
      return this.alpha;
    }-*/;
    
    public native final boolean isDepthEnable() /*-{
      return this.depth;
    }-*/;
    
    public native final boolean isStencilEnable() /*-{
      return this.stencil;
    }-*/;
    
    public native final boolean isAntialiasEnable() /*-{
      return this.antialias;
    }-*/;
    
    public native final boolean isPremultipliedAlphaEnable() /*-{
      return this.premultipliedAlpha;
    }-*/;
    
    public native final boolean isPreserveDrawingBufferEnable() /*-{
      return this.preserveDrawingBuffer;
    }-*/;
  }
}
